Field:
The present invention relates to a field of sample introduction, and more specifically to a sample introduction device.
Description of Related Information:
Ion mobility spectrometer (IMS) is a kind of trace detection device which have recently gained widespread acceptance in the world as she has a very high detect sensitivity, a rapid analyzing speed and a reliable result. The IMS technique identifies samples based mainly on the differences of mobility coefficient of various ions in low electric fields. IMS can rapidly detect drugs, explosives, poisonous gases, biogas and the like, and may be widely employed for military (chemical warfare agent detection) or civil (anti-terrorism, drug control and the like) purposes, and plays an important role in many aspects, such as ensuring national security, maintaining social stability and strengthening national defense and improving national economy and the people's livelihood. However, alarm failures and false alarms are easy to occur when the IMS is solely used to detect complex compounds. Therefore, various combined techniques aimed to improve resolution of analyzer arise. Gas chromatograph-ion mobility spectrometer (GC-IMS) couples GC having an excellent separation capability with IMS having a quick response and a high sensitivity to effectively avoid problems from low identifying capacity of GC and cross sensitivity of IMS when IMS detects mixtures. GC-IMS can obtain three dimensional spectrogram of retention time of color spectrum, drift time and signal intensity, and can effectively identify a sample of complex components. GC-IMS has a detection limit superior to a magnitude of ppb (part per billion) and an identification time ranged from a few minutes to tens of minutes. Compared to other combined techniques, GC-IMS is characterized in simple interfaces, low maintenance cost, high price-quality ratio, etc. Therefore, GC-IMS develops rapidly in recent years, and has advantages of small scale and portability. GC-IMS technique will be one of important tendencies in security check field in the future.
Sample introduction devices are essential to GC-IMS. Sample introduction devices and sample introduction methods have an effect on both a use range of equipment, and a response difficulty and an accuracy of equipment for tested objects. Separate IMS can match with various sample introduction devices, which is a mature technology. Separate GC generally employs headspace sampling methods, which can omit complex pretreatment of samples (suitable for rapid detection). However, with the headspace sampling methods, a certain amount of samples will be “destructively” obtained. Therefore, the headspace sampling methods are not suitable for rapid on-site detection of trace gas without unpacking. Chinese Patent Publication CN1296564A discloses a handheld GC-IMS detector and provides a sampling method for samples attached on surface and gas samples. Specifically, the above reference employs a porous ribbon or coat the ribbon with an absorbing media to adsorb samples of interest, and transmits a portion of the ribbon that has absorbed the samples to a desorption device for sample separation and detection. Although the above reference discloses a rapid detection method adapted for gas samples and samples attached on surface without unpacking, its adsorbing effect is unsatisfactory, and alarm failures and false alarms of instruments are easy to occur.
As such, existing IMS and GC sampling techniques are not suitable for rapid on-site GC-IMS detection without unpacking. Therefore, there is a need for a sample introduction device without unpacking.